Why submarines and ASW forces had to train together

The discussion begins with the V and W destroyers and L-class submarines inherited from the First World War. A navy cannot properly develop either submarine operations or ASW without credible opposing forces to practise against. Submariners need capable hunters to test whether they can penetrate a screen, while escorts need capable submarines to expose weaknesses in detection and attack methods. Britain therefore had unusually large active forces on both sides of the problem during much of the interwar period. This reciprocal training relationship shaped the design and doctrine choices that followed.